Los Angeles air basin experiences the worst air quality in the
United States of America. It is required to meet federal air quality standards
of 8-hour ozone, and annual and daily PM2.5 standard by 2031, 2025, and 2019,
respectively.Substantial emissions
reduction is needed to meet the standard.Numerical modeling approach was utilized to develop strategies to attain
the standards.The Los Angeles air basin
needs over 80 % reductions of NOx emission from 2012 level to meet the 8-hour
ozone standard in 2031.This ozone
strategy is expected to benefit PM2.5 and greenhouse gas reduction goals.

2.

- 일시: 2016.12.9. (금) 15:30~

- 주제: Impacts of Cooling Roofing Technology in the Los Angeles.

- 내용 :

Cool roofs are designed to reflect a larger fraction of incident
sunlight than traditional roofs, reducing the urban heat island effect and
leading to a reduction in emissions from decreased air conditioning use.Lower daytime ambient temperatures and
reduced NOx emissions from energy production should slow the formation of ozone
and PM2.5.However, widespread adoption
of cool roofs in a large urban area like the South Coast Air Basin of
California may change important meteorological parameters that govern pollutant
concentrations such as the planetary boundary layer height and the ventilation
rate.In additional, several cool
roofing materials reflect UV radiation more effectively than traditional
roofing materials, increasing the path length for ozone formation, potentially
leading to an increase in ozone concentrations.

We developed a comprehensive database of rooftop area apportioned by
sector to project changes in albedo in response to potential air pollution
control strategies within the South Coast Air Basin, a region encompassing the
greater Los Angeles area with 17 million residents and significant air
pollution problems.MODIS-derived
high-resolution albedo measurements under a current and a future policy
scenario were used along with the Weather Research and Forecasting (WRF) model
to simulate Southern California meteorological fields for each day of 2012
under each scenario.The Community
Multi-scale Air Quality Management System (CMAQ) was then employed to forecast
changes in ozone and PM2.5 concentrations under future emissions scenarios and
meteorology.The multi-wavelength albedo
parameterization used to calculate photochemical rate constants within CMAQ was
modified to capture the effects of increased UV reflection from widespread cool
roof implementation.Results of these
simulations can help guide existing cool roof policies at the state and
national level.Findings will inform
the development of an Ozone and PM2.5 control measure focused on the strategic
implementation of cool roof technologies and improvement of existing local cool
roof ordinances in the South Coast Air Basin.